Conventionally, there have been known compatibility determination apparatuses that determine compatibility between elements such as programs, drivers, contents, etc., for use in an electronic music apparatus. In such compatibility determination apparatuses, some are adapted to check the matching between versions of functional blocks at start of power supply to the apparatus, and continue the operation thereof as long as there is no version mismatch. On the other hand, if there is a version mismatch, the apparatus gives a warning to a user. See for example Japanese Laid-open Patent Publication No. 2004-56401.
With the above conventional compatibility determination apparatus, in some cases, compatibility between elements cannot be properly determined by the version check. For example, there can be cases where a music content reproducing program of version 3.0 can reproduce music contents of version 1.0 but cannot reproduce those of version 2.0. In another example, a reproducing program of version 4.0 can reproduce music contents of versions 1.0 and 2.0. In such a case, the reproducing program of version 4.0 is called compatible with music contents of version 1.0 or higher.
Nevertheless, if a music content of version 3.0 becomes available after the appearance of the reproducing program of version 4.0, it is not guaranteed that the reproducing program of version 4.0 can reproduce the music content of version 3.0 (even though higher than version 1.0), although it is correct to state at the time of appearance of a music content of version 2.0 that the reproducing program of version 4.0 is compatible with music contents of version 1.0 or higher. However, this statement does not guarantee that the reproducing program of version 4.0 can reproduce music contents of version 3.0 or higher, which appear after the appearance of the reproducing program of version 4.0. In other words, there is a possibility that compatibility between the reproducing program and music contents is not always maintained at the discretion of contents providers. On the other hand, there can be cases where the compatibility is maintained to enable the reproducing program of version 4.0 to reproduce music contents of version 3.0.
As described above, when a new version of some element becomes available, the conventional compatibility determination apparatus can no longer reliably determine whether there is compatibility between that element and other elements. For example, even when the compatibility is maintained in actuality, a statement that there is a possibility of incapability of reproduction is sometimes displayed. In some cases, the reproduction of music contents becomes impossible without any statement of reasons, which confuses the user.
In order to ensure the compatibility between a reproducing program and a music content, the reproducing program can be updated to its latest version upon each appearance of a new version of the music content. If the already installed program is compatible with the new version of the music content, such updating is rather unnecessary and the user's updating operation is wasteful and laborious. Updating failure, if any, can make the user's system partly or entirely inoperative, and therefore, it is preferable that the frequency of updating operations be reduced to a minimum.
The above described problem can occur not only between a reproducing program and a music content, but also between programs (for instance, between a main CPU program and a sub CPU program), between a CPU program and a device driver, and between a device driver and a program.